There are many apparatuses whose purpose is to strengthen the lower back thighs and legs. U.S. Pat. No. 4,483,531 to Lasemann et al. issued Nov. 20, 1984 shows an apparatus containing two rebounding bodies separated by a distance with its rebounding surfaces angled away from the horizontal plane of the apparatus. The purpose of this apparatus was to allow the exerciser to jump with one foot on each of the rebounding surfaces. There is no adjustment to the angle of inclination of the rebounding surfaces. Jumping between the two surfaces with both feet at the same time is not contemplated by the specification of this patent.
U.S. Pat. No. 4,730,826 to Sudmeier issued Mar. 15, 1988 is drawn to an apparatus containing a single rebounding surface which is V shaped. The rebounding effect of jumping from one side of the rebounding surface to the other is diminished because the two sides of the surface are connected together and do not allow independent action between the two sides. This does not allow the opposite side of the rebounding surface to return to neutral position before the next impact.
U.S. Pat. No. 4,824,100 to Hall et al. issued Apr. 25, 1989 describes two rebounding bodies being affixed together having no space between the rebounding bodies.
U.S. Pat. No. 4,880,226 to Krantz issued Nov. 14, 1989, U.S. Pat. No. 4,907,796 to Roel-Rodriguez issued Mar. 13, 1990, U.S. Pat. No. 5,074,550 to Sloan issued Dec. 24, 1991 are drawn to exercise apparatuses which allegedly strengthen legs, back, and hips. The apparatuses described in these patents do not anticipate or suggest an apparatus containing two rebounding surfaces with adjustable inclination and a space between the two rebounding bodies.